For what do you need the millimeter paper? For plotting? Then use TAChart, otherwise you'll have to reinvent scaling of coordinates, generation of axis labels, positioning titles and legends and a lot more. PlotPanel might work too, it is not actively maintained, and in fact, I don't know whether it even compile.
For using TAChart you should have a look at the introductory tutorial: wiki.lazarus.freepascal.org/TAChart_Tutorial:_Getting_started